It is 好物沉歸底
From my answer at another site
It is 「好物沈歸底」"Good stuff sinks to the bottom"
It means: " the best things are often hidden under ordinary things. " which means: "We have to get to the bottom to unveil the full value of something"
Example: 「好物沈歸底,啲湯渣先至係碗湯嘅精華。」
「good things sink to the bottom, the leftover ingredients at the bottom of the bowl are actually the best part of the soup」(if you don't get to the bottom of the soup bowl, you wouldn't get to these goodies)
Say you want to hire someone-- after interviewing 30 of 40 people who applied for the job, you thought you've found the one you wanted, but I would advise you, and say: " 好物沈歸底- may be the best person is among the last ten, you should finish interviewing them all."